One way to make a decorative accent is to twist the metal. Basically, you heat the section of metal to be twisted, clamp one end in a vise, grab the other end with a twisting wrench, and twist. Direction is your discretion, except where the twist has to be made in both directions and then any decision is removed from consideration.

Some twists can also be done cold, but what fun is that.

One excellent source of information is the Old Dominion Blacksmith Association's article on twisting: The Twist Class

Manual Twisting Machine

Lantern Twisting Machine

Automatic Twisting Machine

Types of Twists

There are a multitude of different twists and new ones being developed occasionally. Some of the more common are:

plain (just heat and twist)

veined (groves down each side and twist)

rope (really just veined with the corners chamfered and a mild cross-hatching added for appropriate texture)

Here is a tough one. Most blacksmiths are fooled by it but
the general public doesn't see the trick at all.
(Easy actually. It's three pieces. One is ¼" by ½"
and the other two, are 1/4" square. They were forge
welded on each end, and then twisted tightly.

A simple but elegant twist, round and square

Rope twist

This one is heated, flattened where the twist is to be made, and then twisted a half turn. Simple, I think.

3/8 bar Swaged in a 3/16 tenon swage on diamond and then twisted

pineapple twist

A wave. Bend bar in half, taper bent end, unbend

Alligator twist on knife handle

Another alligator twist handle, this one places more emphasis on the texture. I really like that.

Another alligator twist handle, this one rounded more deemphasizing the texture

How to Make a Pineapple Twist

found at Diary of a Wandering Hen
http://wanderinghen.wordpress.com/category/ren-faire-shenanigans/blacksmithing-ren-faire-shenanigans/

Fig. A - Fig. E, from left to right.

Steps in making a pineapple twist:

Mark a deep groove down the center of a piece of heated square stock. Make this mark on all four sides of the stock. (Fig. A)

Place in vice and make a 3/4 twist. (Fig. B)

Square all four sides on the anvil. (Fig. C)

Punch another groove down the center of each four sides, as in step 1. (Fig. D)

Untwist in vice 1/4 twist. Watch the twist to see if it looks right. True up on anvil with a wooden mallet. You now have a completed pineapple twist. (Fig. E)

The adjustable length twisting jig is a very useful tool for making double reversed twists in various sized bars. It will allow you to make virtually perfect twists every time, if you have the bar evenly heated when its placed into the wrench jaws. I like to use an old "Ford wrench" to make my double handled twisting wrenches out of. Using a double handled wrench will allow you to apply an even force to the bar and not cause it to be bent out of alignment during the twisting process. Be sure you use the right kind of welding rod when welding the high carbon steel wrench heads to the jig, or the welds will break off the first time you use the jig. I use "UTP-65" for all such welds, expensive, but worth every penny. Also, because your hands rotate under the hot iron during twisting, the hot scale that falls off will land on your hand and wrist. Beginners usually find this uncomfortable, but you will soon get used to it, and it causes no damage.